Heater and air running together.

[daveworcester]

Heater and air runs at the same time. Service person says it's the thermostat. To fix it I have to reset breaker. Seems to happen a couple times a month.Anyone experience this issue?

[chaconmorales]

Hi daveworcester,

Thanks for reaching out to the Community. I am sorry that you are having issues with your heating and air conditioning running at the same time in your Nest Thermostat. But no need to worry. I'd be happy to help you.

Before we get started with further troubleshooting, let me ask you some important questions:

1. What Nest Thermostat model do you have?
2. Does the thermostat display show any error codes or messages?
3. Are you able to share a picture of your wiring?
4. Have you followed any troubleshooting already?
5. What type of system do you have? (Heat Pump or conventional type)

Potential Causes:

• Incorrect System Setup: Your Nest thermostat might not be correctly configured for your HVAC system.
• Wiring Issues: Problems with the wiring between the thermostat and your HVAC system could be causing the issue.
• HVAC System Malfunction: There might be a problem with your HVAC system itself.

Here are some basic steps you can try to troubleshoot the issue:

Check Thermostat Settings:

• Ensure your thermostat is set to the correct mode (heat or cool).
• Verify that the fan setting is correct (auto, on, or circulate).
• Check for any advanced settings or schedules that might be causing conflicts. You can check the following guide to Troubleshoot strange heating or cooling behavior.
• I understand that you have already restarted the thermostat: You can also check the following article to Restart or reset a Nest thermostat depending on your deviceś model and make sure the correct process is followed.
• Check that your system doesn't need maintenance.

Note: If you're not comfortable working with electrical wiring, consult a qualified technician (Nest pro).

Please keep me posted.

Best regards,

Mario

[bcarle8563]

I had the same problem with our condo in FL. We are there several times a year, otherwise it's unoccupied. We arrived a month  ago to find the temp at 101 F. Outside temp was 86. Fan was running and pumping out heated air. After several tries to start the a/c, I shut the system down. HVAC tech came next morning and did some troubleshooting. He said the a/c was running along with the  heater (electric). He  tried several times to shut the heater down with no success. He disconnected the heater wiring in the hvac unit and didn't seem interested in going any further. A few days later I received a call from FPL regarding a spike in our electricity usage. This started 21 days ago and was running 24/7, which explained the massive utility bill we received. In addition to any advice on what may have happened and how to fix it, is there a way to set a text  or email alert when a certain high or low temp is reached? There was a message in  the app about the safety temp being reached, but I didn't see it until after the fact.

Any help would be appreciated.

Thanks

[chaconmorales]

Hi bcarle8563,

Thank you for posting here in the community. I am sorry that you are having issues with your heating and air conditioning running at the same time in your Nest Thermostat. But no need to worry, help is here.

Before we get started with further troubleshooting, let me know if you have tried the steps listed in the original post and response. In addition, to know more details about your issue, please provide me with more information by answering the questions listed above.  

Please keep me posted.

Best,

Mario